In addition to endoscopes with a fixed viewing direction parallel to or at an angle to the longitudinal axis of the shaft, endoscopes with an adjustable viewing direction are increasingly being used. Free adjustability of the viewing direction within a predetermined angle range can permit substantially more flexible use and can thus allow medical personnel to work more quickly, under less strain and therefore also more safely and more economically.
In order to allow an endoscope to be autoclaved and therefore to be re-used many times over for medical applications, the beam path of the endoscope has to be protected by a hermetically tight sheath against entry of moisture even at a high temperature and at an overpressure. To ensure that forces and movements generated on an actuation device outside the hermetically tight sheath can be transmitted into the interior of the hermetically tight sheath, a number of concepts were developed based on a magnetic coupling between magnets outside and inside the hermetically tight sheath.
EP 0 907 900 B1 (first published as WO 98/44376 A1) describes an endoscope with a hermetically tight sheath. A movement of an actuation device is transmitted magnetically from a ring arranged outside the sheath to a ring arranged inside the sheath. Neither the outer ring nor the inner ring is axially movable. A rotation of the inner ring is transmitted by means of a thread to an axially movable structural element.
EP 2 353 493 A1 describes a medical instrument with a magnetic actuator. One or more magnets outside and inside a hermetically tight sheath are axially movable and also rotatable about a common axis, in order to transmit axial forces and also torques by magnetic coupling. Axial forces can be transmitted for focusing or for other actions (paragraph [0019]).
EP 2 430 970 A2 and EP 2 430 971 A2 describe endoscopes with an adjustable viewing direction. A rotation movement of an actuation element is converted by means of a gear into an axial movement of a draw tube.
DE 10 2011 012 426 A1 describes an endoscopic instrument for use by one hand. An adjustment element is arranged on the outside of the instrument in such a way that it can be moved ergonomically with one finger of a hand that holds the instrument, in order to adjust a viewing direction of the endoscopic instrument (paragraphs [0009], [0036], [0051]).